Liquid crystal display devices are widely used as displays in portable electronic devices such as mobile telephones, and in such devices as televisions and personal computers. In general, however, liquid crystal display devices, although they provide good viewability from the front, have been known to have a narrow viewing angle, and efforts have been made to widen the viewing angle, one being a proposal of a polarizer in a waveguide array made of a plurality of tapered waveguides on the light emission side (refer to Patent Reference 1 noted below).
In this polarizer, as shown in FIG. 17, a waveguide array made of a plurality of tapered waveguides 101 is disposed on one surface of a polarizer element 102. Each of the waveguides 101 is made of a resin material having a refractive index of approximately 1.45 to 1.65. Light that is incident from the light incidence surface, on which the surface area of the waveguides 101 is large, is reflected at the side surfaces of the waveguides, and is emitted from the light emission surface that has a small surface area in the condition in which the angle distribution is widened. Therefore, in Patent Reference 1, there is a description to the effect that, by disposing this polarizer on the light emitting surface of a liquid crystal panel, the angle distribution of light emitting from the liquid crystal panel is widened, enabling the image to be viewed from a greater angle.
There also has been a proposal of a refractive index changing composition having radiation sensitivity, for the purpose of forming an optical waveguide or light diffusing sheet or the like having a fine refractive index pattern (refer to Patent Reference 2 noted below). According to the method of forming the refractive index pattern disclosed in this reference, after forming a coating film by coating the solution of the above-noted composition onto a substrate, the coating film is exposed to radiation through, for example, a pattern mask. When this is done, a photochemical reaction is induced in the composition in the regions exposed to the radiation, changing the refractive index and resulting in a difference in refractive index with respect to regions that are not exposed to the radiation. The description notes that the above-noted composition is an optical material such as for optical waveguides, light diffusing sheets and the like.